Usual frictional machine parts such as gears, bearings, rotors, shafts, crankshafts and turbines requires lubrication. If the lubricant supply ceases or becomes insufficient, heat is produced at frictional portions, leading to wear or rupture of such portions. Depending on the purpose of the machine, however, there are cases where no lubricant can be used, or where great limitations are imposed on the use of lubricant. For example, in devices for manufacturing foods or medicines, great care is paid lest lubricant should be occasionally introduced into the products. Great care is also paid in the case of medical devices. Further, timepieces or the like, which are used by general consumers, require lubricants for prolonged use.
Further, micro-machines (i.e., minutia precision machines) comprising parts of about 1 mm or less in size, can not use any lubricant because of the extremely small size of the parts. Making the surface as smooth as possible is the sole way of providing for a satisfactory frictional property of micro-machines.
With general machine parts, however, the possibility of hazardous leakage of the lubricant exists even if great care is taken. With timepieces or the like, which are used by general consumers, it is practically impossible to use a lubricant. The surface of micro-machine parts may be made smooth by a photo-lithographic process. In this case, however, limitations are imposed, and currently sufficient durability can not be obtained.
At any rate, it has been impossible to obtain a high performance machine part offering low frictional resistance.
In another aspect, in tape recorders, VTRs, DATs and other recording/reproducing devices, in which magnetic tapes are driven, great care is taken lest scars or scratches are produced on the tapes during running. Scars or scratches produced on the recording medium will interfere with necessary functions of recording and reproduction. Further, scars or scratches produced on the back surface of the recording medium will undesirably cause transferred scars or scratches when a medium such as a tape is wound.
VTRs and DATs are multi-functional and high performance devices. They are particularly required to have long life and be highly reliable. VTR cylinder heads are rotated at high speeds of about 1,000 to 6,000 rpm. Therefore, if abnormalities occur in the rotating mechanism, the image reproduction or reliability is greatly affected, and trouble in the rotating mechanism will cause defective reproduction.
Generally, frictional parts such as bearings, rotors, shafts, crankshafts and turbines require a supply of lubricant. If the lubricant supply ceases or becomes insufficient, the frictional sections generate heat, leading to wear and rupture.
To avoid such defficiencies, it has heretofore been the practice to make only the frictional surface in contact with the running tape as smooth as possible. In addition, to enhance the lubricating property of the frictional surface of a device, it has been typical practice only to coat the frictional surface with lubricant or to make the frictional surface as smooth as possible.
However, making the frictional surface as the contact surface of the running tape as smooth as possible also reduces the friction of the tape during running. In addition, where lubricant is supplied to the frictional surface of the device, the possibility of lubricant leakage exists. If oil leakage occurs in a VTR cylinder head bearing section, lubricant is spattered onto nearby parts due to high speed rotation. This can affect the VRT tape or the like adversely. Besides, there is a limitation on making smooth the frictional surface itself.
In a further aspect, game balls such as those for pachinko, smart ball and bowling games can be readily contaminated. If they are contaminated, they may fail to roll smoothly, or may cause clogging of the game machine during the game, or they will be worn out to deteriorate their slip. Therefore, it is necessary to make the game ball surface as smooth as possible to permit smooth rolling by washing or polishing. Heretofore, game balls are polished with cloth or the like, and in game places this operation is continued until late at night. Further, it is well known to increase the lubricity of the ball surface by making the surface as smooth as possible or coating a lubricant on the surface.
However, limitations are imposed on permitting smooth rotation of game balls by making the surface smooth during the molding process. In addition, where a lubricant is coated, the lubricant film can be separated or worn out during use.